Solenoid valve

ABSTRACT

In at least some implementations, a solenoid valve includes a housing, a bobbin and an armature. The bobbin is received at least partially within the housing and has a body about which a coil is provided. A fluid flow path including an inlet and an outlet and a valve seat is defined by at least one of the housing or the bobbin, and the armature is moveable relative to the valve seat to control flow through the fluid flow path.

REFERENCE TO CO-PENDING APPLICATION

This application is a divisional of U.S. patent application Ser. No.16/416,340 filed May 20, 2019, which is a divisional of Ser. No.15/461,537 filed Mar. 17, 2017 now U.S. Pat. No. 10,352,471 issued onJul. 16, 2019, which is a divisional of Ser. No. 14/896,764 filed Dec.8, 2015 now U.S. Pat. No. 9,631,736 issued on Apr. 25, 2017, which is anational phase of PCT/US2014/041707, filed Jun. 10, 2014 and claims thebenefit of U.S. Provisional Application No. 61/833,228 filed Jun. 10,2013. The entire contents of these priority applications areincorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates generally to a solenoid valve for fluidflow control.

BACKGROUND

Solenoid valves are used in a wide range of devices to control fluidflow. Such valves utilize an armature driven by a magnetic fieldselectively generated by selectively providing electric current to acoil. The valves may include many components, and especially when thecomponents are relatively small, assembly thereof and ensuring properposition of the components may be difficult. Some solenoids are usedwith engine fuel system components, such as on or in a carburetor for anengine system that does not include a battery. In at least theseimplementations, it is desirable to reduce the current needed to drivethe solenoid as the electrical energy available in such systems may belimited.

SUMMARY

In at least some implementations, a solenoid valve includes a housing, abobbin and an armature. The bobbin is received at least partially withinthe housing and has a body about which a coil is provided. A fluid flowpath including an inlet and an outlet and a valve seat is defined by atleast one of the housing or the bobbin, and the armature is moveablerelative to the valve seat to control flow through the fluid flow path.

A method of assembling a solenoid may include the steps of:

-   -   providing a bobbin;    -   coupling a terminal to the bobbin in a first position wherein a        gap is provided between the terminal and bobbin;    -   providing a coil on the bobbin and having a wire connected to        the terminal; and    -   moving the terminal to a final position relative to the bobbin        which reduces or eliminates the gap and provides slack in the        wire connected to the terminal. The method may further include        inserting an armature through an open end of the bobbin,        inserting an armature stop through said open end of the bobbin        after the armature is inserted, and/or installing a cap that        engages one or both of the terminals and the armature stop so        that installing the cap also moves one or both of the terminals        and the armature stop to their final installed position. The        armature and method may provide a so-called “drop-down”        installation wherein the valve components are installed in the        same direction to facilitate assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of preferred embodiments and bestmode will be set forth with reference to the accompanying drawings, inwhich:

FIG. 1 is a sectional view of a bobbin;

FIG. 2 is a top view of the bobbin;

FIG. 3 is a bottom perspective view of the bobbin;

FIG. 4 is a sectional view like FIG. 1 and showing a pair of terminalsbeing inserted into terminal cavities of the bobbin;

FIG. 5 is a fragmentary side view showing a portion of one terminal anda portion of the bobbin;

FIG. 6 is a side view of a terminal;

FIG. 7 is a sectional view showing the terminals in a preliminaryinstallation position;

FIG. 8 is a fragmentary view showing a terminal in its preliminaryinstallation position;

FIG. 9 is a sectional view like FIG. 7 and including a wire coil on thebobbin and connected to the terminals;

FIGS. 10 and 11 are fragmentary side views showing the wire coilconnected to each of the terminals;

FIG. 12 is a sectional view showing the bobbin received within ahousing;

FIGS. 13 and 14 are top and bottom perspective views of the housing;

FIG. 15 is a sectional view like FIG. 12 and including a valve member;

FIG. 16 is a sectional view like FIG. 15 and including an armature an abiasing member for the armature;

FIG. 17 is a sectional view like FIG. 16 and including an armature stop;

FIG. 18 is a perspective view of the armature stop;

FIG. 19 is a sectional view like FIG. 17 and including a cap;

FIGS. 20 and 21 are top and bottom perspective views of the cap;

FIG. 22 is a sectional view like FIG. 19 illustrating a final assembledposition of the components of the solenoid valve;

FIG. 23 illustrates the armature in its open position;

FIG. 24 illustrates the armature in its open position and the valvemember against the valve seat;

FIG. 25 illustrates an alternate solenoid valve;

FIG. 26 is a perspective view of a carburetor including a solenoid valveas described; and

FIG. 27 illustrates a solenoid carried by a device with additional sealsprovided.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring in more detail to the drawings, FIG. 26 illustrates a solenoidvalve 10 carried by a carburetor 12 to control the flow of a fluid (e.g.gaseous, like air or liquid, like fuel) within one or more passages inthe carburetor. The solenoid valve 10 may be received within a cover 14connected to a main body 16 of the carburetor 12, or otherwise carriedby or associated with the carburetor. While shown in use with adiaphragm carburetor, the solenoid valve 10 may be used with any type ofcarburetor or with other devices.

Referring to FIGS. 1-3, the solenoid valve 10 includes a bobbin 20 witha body 22 including an internal passage 24, and spaced apart andradially outwardly extending flanges 26, 28. Terminal cavities 30 may beprovided extending generally axially from an upper one of the flanges26, and a fluid flow path or passage 32 may be provided at the oppositeflange 28. The fluid passage 32 may extend into and be defined at leastin part by a cylindrical boss or reduced diameter portion 34 carried bythe body 22. The boss may be provided adjacent to one end of theinternal passage 24, opposite to an open end of the internal passage.The boss 34 is open at one end defining an inlet 36 of the passage 32and an internal valve seat 38 is defined at its other end. Downstream ofthe valve seat 38, one or more fluid outlets 40 are provided in the body22. The valve seat 38 faces the internal passage 24 and may have atleast a portion that is radially smaller than the internal passage 24(e.g. extends inwardly relative to and/or provides a shoulder in oradjacent to the internal passage), and an armature 42 (FIG. 16) receivedin the passage 24 may open and close, or control the opening and closingof, the valve seat 38 as the armature 42 is driven by the solenoid. Inthe illustrated embodiment, four outlets 40 are provided. While notrequired, the bobbin 20 and all of the features described aboveincluding the valve seat 38, body 22, terminal cavities 30 and fluidflow passages/ports may all be integrally provided in the same componentand may be formed in the same piece of material. In at least oneimplementation, the bobbin is molded from a plastic material andincludes all of these features as molded.

Electrical terminals 44 are provided in the terminal cavities 30, asshown in FIGS. 4 and 5. The terminals 44 are formed from metal, areconnected to a wire of the solenoid coil 46 (FIG. 9), and define part ofthe electrical circuit of the solenoid valve 10. The terminals 44 may begenerally thin strips of metal that are pressed into the terminalcavities 30. To retain the terminals 44 in the cavities 30, theinsertion end 48 of the terminals 44 and/or the cavities 30 may includea connection feature. As shown in FIGS. 5 and 6, the connection featureincludes serrations 50 on the insertion end of the terminals 44,although other connection features may be used in addition to or insteadof the serrations 50. The serrations 50, in the embodiment shown, areadapted to dig into the material defining the terminal cavities 30 tofirmly retain the terminals in the cavities. Spaced from the insertionend 48, the terminals 44 may include one or more wire retainer featuresto facilitate retention of the wire 46 on the terminals. In at leastsome implementations, the wire retainer features may include outwardlyextending shoulders 52 spaced apart by a smaller neck 54 about which thewire 46 is wrapped or crimped.

As shown in FIGS. 7 and 8, the terminals 44 may be inserted to aninitial depth within the cavities 30 that defines a preliminaryinstallation position and leaves a gap 56 between the insertion end 48of the terminals 44 and a bottom of the cavities 30. The initial depthmay be controlled by engagement of a lower one of the shoulders 52engaging the wall defining the cavities 30, or by some other means.

With the terminals 44 installed to their initial position on the bobbin20, the wire coil 46 can be provided on the bobbin 20. In one form, thewire coil 46 is provided by tying one end of a wire to one of theterminals 44, winding the wire 46 a desired number of times around thebobbin body 22 between the flanges 26, 28, and then tying off the otherend of the wire 46 to the other of the terminals 44. As shown in FIGS.5, 8, 10 and 11, the terminal cavities 30 may include slots 58 toaccommodate the wire 46 between the terminals 44 and the bobbin body 22.The bobbin 20 may be symmetrical such that the wire 46 may be initiallywrapped onto either terminal 44. The wire ends may be soldered to theterminals or otherwise connected, as desired.

After the wire 46 is provided on the bobbin 20, the bobbin may beinserted into a housing 60, as shown in FIG. 12, with the housing 60shown in FIGS. 12-14. The housing 60 may be generally cylindrical andopen at an upper end 62 that is received adjacent to the terminals 44.To reduce vibrations and/or help retain the bobbin 20 within the housing60, the bobbin flanges 26, 28 may be relatively closely received withinan interior surface 64 of the housing 60, if desired. The lower end ofthe housing may include and inwardly extending wall 66 with an opening68 through which the boss 34 extends. Inwardly extending tabs 70 may bereceived within the outlets 40 formed in the bobbin 20 adjacent to thevalve seat 38, and adjacent to the interior passage 24 of the bobbin.While any number of tabs 70 may be provided, as shown, four tabs areprovided with one tab 70 extending into each of the outlets 40. Thehousing 60 may be formed from metal and may define part of the magneticflux path of the solenoid valve as will be described.

To improve the sealing/closing of the valve seat 38 when desired, asshown in FIG. 15, a valve member 72 may be provided within the bobbin'sinternal passage 24, adjacent to the valve seat 38. The valve member 72may be formed from any suitable material and may be generally circularand sized for receipt in the internal passage 24 and to engage and closethe valve seat 38. The valve member 72 may be independently receivedwithin the internal passage 24 such that it can move independently ofand is not directly connected to another component. In this manner, itmay act as a check valve to prevent reverse flow from the outlet(s) tothe inlet and it may improve closing and sealing of the valve seat 38 aswill be described further.

Next, as shown in FIG. 16, the armature 42 may be inserted into thebobbin internal passage 24 with one end 74 adjacent to the valve member72 and/or valve seat 38 and the opposite end 76 within the bobbin body22 and surrounded by the solenoid coil 46. The armature 42 may beferromagnetic and is slidably received within the internal passage 24 sothat it may move relative to the valve seat 38 as will be described. Abiasing member, such as a spring 78 may be received within the internalpassage 24 and have one end engaged with the armature 42, which may havea reduced diameter at end 76 over which a portion of the spring 78 isreceived. The spring 78 biases the armature 42 into engagement with thevalve member 72 so that the valve 10 is normally closed. That is, unlessthe armature 42 is moved away from the valve member 72 by an magneticforce generated by the solenoid, the spring 78 urges the armature 42into the valve member 72 which engages and closes the valve seat 38 toinhibit or prevent fluid flow through the valve seat 38.

As shown in FIG. 17, an armature stop 80 is provided in the open end ofthe bobbin 20 to close the open end, provide a reaction surface for thespring 78 and a stop surface that may be engaged by the armature 42 tolimit its travel. As shown in FIGS. 17 and 18, the armature stop 80 mayinclude a spring retention feature, such as a reduced diameter nose 82at one end, a stem 84 closely received against the bobbin in theinternal passage 24, an outwardly extending head 86 and a protrudingcylindrical boss 88. The stem 84 may include retention features, such asoutwardly extending barbs 90, to engage the bobbin 20 within theinternal passage 24 to firmly retain the final assembled position of thearmature stop 80. At the point of the assembly shown in FIG. 17, thearmature stop 80 may be only partially pressed into the bobbin 20 with alower end of the head 86 still spaced from an internal shoulder 92 ofthe bobbin 20. The head 86 may be generally cylindrical, designed tosubstantially close the open end of the bobbin 20 and may includerecesses 94 to accommodate the terminal cavities 30. The boss 88 mayinclude outwardly extending barbs 96 or other retention features for acap that may be installed over the open end of the housing 60, bobbin 20and over the armature stop 80. The adjacent end of the armature stop 80may be engaged by the armature 42 and provide a positive stop or limitto the armature movement.

FIGS. 19-21 illustrate the cap 98 and its assembly onto the solenoidhousing 60, armature stop 80 and bobbin 20. The cap 98 may have agenerally cylindrical sidewall 100 leading to an upper wall 102. Theupper wall 102 may include an opening 104 that receives the armaturestop boss 88, and a pair of slots 106 through which the terminals 44extend when the cap 98 is inserted onto the terminals 44 and pressedinto its assembled position. If desired, as the cap 98 is installed toits final position, the cap 98 may engage the head 86 of the armaturestop 80 and drive the armature stop to its final position, shown in FIG.22. In this position, the armature stop 80 is engaged with the bobbin 20within its internal passage 24 and the head 86 is trapped between thebobbin 20 and cap 98. This movement of the armature stop 80 may compressthe spring 78 between the armature stop 80 and armature 42 to provide adesired spring force acting on the armature. A lower edge 108 of the capsidewall 100 may be pressed flush against the open end of the housing 60to provide a positive stop for the cap 98 that may be visually verified.Of course, the cap sidewall 100 could be received over or within thehousing 60, if desired. The cap 98 may provide a dust/contaminant shieldfor the soldered wire-to-terminal connection, and the solenoids internalcomponents generally. The cap 98 may provide support for the terminals44 so that they are less likely to be unduly flexed and or displacedfrom their cavities 30. And the cap 98 may help retain the solenoidvalve 10 within a cavity 110 in which the solenoid valve 10 is received,for example, as shown in FIG. 26.

In the implementation shown, the final assembly step is to move theterminals 44 from their initial position to their final assembledposition shown in FIG. 22. This can be done by simply pressing theterminals 44 further into their cavities 30, and may be done at the sametime the cap 98 is installed. This movement of the terminals 44 mayprovide some slack in the solenoid coil wire 46 to create some stressrelief for the wire 46 and ensure that it is not stretched or undulytaut in use. This reduces the likelihood that the wire may break andcause failure of the solenoid. This later provided stress relief mayalso permit the wire to be wound around the bobbin 20 and connected tothe terminals 44 without having to provide slack at that time, and thismay simplify the wire winding process.

In use, when electricity is supplied to the terminals 44, the wire coil46 generates a magnetic field that displaces the armature 42 against thespring 78 and into engagement with the armature stop 42, as shown inFIG. 23. This permits the valve member 72 to be moved away from thevalve seat 38 by fluid flow through the inlet 36 and toward theoutlet(s) 40. However, the reverse flow of fluid may be prevented by thevalve member 72, as shown in FIG. 24, even if the armature 42 is in itsopen position as such reverse fluid flow engages the valve member 72 andmoves it onto the valve seat 38 to close the valve seat. Whenelectricity is not supplied to the terminals 44, the armature 42 isreturned to its closed position by the spring 78 and fluid flow throughthe valve seat 38 is inhibited or prevented by engagement of the valvemember 72 with the valve seat 38.

An alternate solenoid valve 120 is shown in FIG. 25. This solenoid valve120 may be the same as that previously described except as noted below.In this solenoid valve 120, the valve seat 122 and fluid passage 124,including inlet 126 and outlet(s) 128 are formed in the housing 130rather than the bobbin 132. Hence, the bobbin 132 may terminate at itslower flange 134 and not include the boss 34 as in the prior embodiment.The housing 130 may include an inwardly extending wall 136 against whichthe bobbin 132 is received. The wall 136 has an opening 138 throughwhich the armature 42 extends, and this provides the housing 130 inclose proximity to the armature 42 so that the housing 130 may completethe magnetic flux path as previously described. Otherwise, theconstruction and operation of this solenoid valve 120 may be the same asdescribed and shown for the other solenoid valve 10.

By forming the valve seat 38, 122 integral with the bobbin 20 and/or thehousing 130, rather than as a separate and additional component, thetolerances can be reduced and tolerance stack-up between multiplecomponents eliminated. Further, the integral valve seat 38, 122 andfluid flow paths 32, 124 in the bobbin 20 or housing 130 enable aportion of the housing 60, 130 (e.g. the lower wall and/or its tabs) tobe received close to the armature 42 such that the housing itself(rather than separate washers or rings) can complete the magnetic fluxpath to the armature. Enabling precise location of the tabs 70 or otherportion of the housing 60, 130 in close proximity to the armature 42without interference with the armature 42 also enables the currentrequired to operate the solenoid valve 10, 120 to be reduced compared tosimilar solenoids. This reduced the cost to operate the solenoid valve10, 120 and facilitates use of the solenoid valve with devices that donot have ready supplies of electrical power, such as devices powered bysmall engines that do not have a battery or alternator. The open-endedbobbin 20, 132 and housing 60, 130 are designed so that the remainingcomponents can all be inserted from the same end providing a so-calleddrop-in or top-down installation. And the components can be moved totheir final assembled positions by a single pressing operation thatmoves, for example, the armature stop 80, cap 98 and terminals 44 totheir final assembled positions providing for a simple and low costassembly.

Certain components may also provide more than one function, to improvethe efficiency of the solenoid valve 10, 120. For example, the valvemember 72 may act as a valve seal and a check valve, as noted abovewhich eliminates the cost and tolerance stack-up that would beassociated with an additional check valve. The armature stop 80 mayprovide a stop surface to limit movement of the armature 42 away fromthe valve seat, a retainer for the armature and spring by way of itsfriction or interference fit within the bobbin internal passage 24, andalso a retainer for the cap 98 by way of the retention barbs on theboss. This may reduce the interference between the components and theforce needed to press the components to their final assembled positionwhich could otherwise deform the bobbin and potentially break the wirecausing failure of the solenoid.

FIG. 27 illustrates additional sealing that may be provided when thesolenoid valve 10 or 120 is inserted into a cavity 140 of a device 142.Seals, such as o-rings 144 may be provided between the bobbin 20 and thehousing 60 and/or between the housing 60 and the device 142 within thecavity 140. A further seal 146 may be provided between the bobbin boss34 and the device 142. And these seals may be in addition to sealsprovided by the interference fit between the armature stop 80 and thebobbin 20, and the cap 98 and armature stop 80. Further, the cap 98 mayhave an outer diameter that is larger than the inner diameter of thecavity 140 to provide a press or interference fit between the cap 98 anddevice 142 within the cavity 140.

It will of course be understood that the foregoing description is ofpreferred exemplary embodiments of the invention and that the inventionis not limited to the specific embodiments shown. Various changes andmodifications will become apparent to those skilled in the art and allsuch variations and modifications are intended to come within the spiritand scope of the appended claims.

1. A solenoid valve, comprising: a housing having a cylindrical portionwith an open upper end; a bobbin received at least partially within thehousing and having a body with two cavities formed in the body, and withan internal passage formed in the body; a wire coil carried by the body;a fluid flow path including an inlet and an outlet and a valve seatdefined by the bobbin; an armature received within the internal passageand moveable relative to the valve seat to control flow through thefluid flow path; two terminals each received in a respective one of thecavities and each coupled to the coil; and a cap having openings throughwhich the terminals are received, and the cap having, wherein thecavities, openings in the cap, internal passage and upper end of thehousing are parallel.
 2. The valve of claim 1 wherein the body includesa cylindrical boss at one end that is axially aligned with the internalpassage and parallel to the internal passage, and which has a smallerdiameter than the internal passage, and wherein the valve seat isdefined the boss.
 3. The valve of claim 1 which also includes anarmature stop received at least in part in the internal passage so thatit is engaged by the armature in one position of the armature to limitmovement of the armature away from the valve seat, and wherein the capengages the armature stop.
 4. The valve of claim 3 wherein the capincludes another opening that is between the openings in which theterminals are received, and wherein part of the armature stop isreceived in said another opening and wherein said another opening isparallel to the openings in which the terminals are received.
 5. Thevalve of claim 4 wherein the cap is press fit to at least one of thearmature stop and terminals.
 6. The valve of claim 2 wherein oppositethe upper end, the housing includes an inwardly extending wall and anopening through the inwardly extending wall, and wherein the cylindricalboss extends through the opening through the inwardly extending wall. 7.The valve of claim 1 wherein the cap has a sidewall with a lower edge,and wherein the lower edge is engaged with the open upper end of thehousing.
 8. The valve of claim 7 wherein the lower edge is axiallyengaged with the upper end of the housing.